Self-ligating orthodontic bracket and method of using the same

ABSTRACT

A self-ligating orthodontic bracket includes a bracket body, a slide member, and a resilient member. The slide member is movable relative to the bracket body between an opened position, a first ligating position, and a second ligating position. In the first ligating position and in the second ligating position, a surface of the slide member bounds the archwire slot on a side generally opposite to the base surface to retain the archwire. The resilient member is configured to engage the other of the slide member and the bracket body and has a deformed state for biasing the slide member toward the base surface in at least one of the first and second ligating positions. In the first and second ligating positions, the base surface of the archwire slot and the surface of the slide member are separated by different distances.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/798,675, filed Mar. 15, 2013, the disclosure of which isincorporated by reference herein in its entirety.

TECHNICAL FIELD

The invention relates generally to orthodontic brackets and, moreparticularly, to self-ligating orthodontic brackets and methods of usingthose brackets in orthodontic treatment.

BACKGROUND

Orthodontic brackets represent a principal component of all correctiveorthodontic treatments devoted to improving a patient's occlusion. Inconventional orthodontic treatments, an orthodontist or an assistantaffixes brackets to the patient's teeth and engages an archwire into aslot of each bracket. The archwire applies corrective forces that coercethe teeth to move into correct positions. Traditional ligatures, such assmall elastomeric O-rings or fine metal wires, are employed to retainthe archwire within each bracket slot. Due to difficulties encounteredin applying an individual ligature to each bracket, self-ligatingorthodontic brackets have been developed that eliminate the need forligatures by relying on a movable portion or member, such as a latch orslide, for retaining the archwire within the bracket slot.

There are generally two types of ligation of the archwire to theorthodontic bracket: passive ligation and active ligation. In passiveligation, a closure member bounds the archwire slot such that thearchwire slot has a fixed width dimension (e.g., labially-lingually).Additionally, the archwire located in the archwire slot typically has awidth dimension that is smaller than the width dimension such that thereis a space or gap between the archwire and the archwire slot.

In contrast, in active ligation, an aspect of the bracket activelyimposes a force onto the archwire to seat the archwire within thearchwire slot such that there are generally no spaces or gaps and a snugfit is attained therebetween. The biasing of the archwire into thearchwire slot may be achieved, for example, through the use of aresilient member on the bracket that acts on the archwire to push thearchwire towards the base of the archwire slot.

During the early stages of orthodontic treatment, significant movementof the teeth is generally desired. This typically requires there to besignificant movement of the archwire relative to the brackets on theteeth. Accordingly, during these early stages of treatment, passiveligation of the archwire may be desired to facilitate the relativemovement between archwire and the brackets during these relatively largemovements of the teeth. To achieve passive ligation, relatively small orthin archwires are often used to ensure sufficient space in the archwireslot.

During the finishing stages of orthodontic treatment, however, fine andprecise movements of the teeth may be desired. These movements typicallyrequire excellent control of the archwire within the archwire slot.Thus, during these final stages of treatment, active ligation of thearchwire may be desired to facilitate, for example, excellent torque androtational control of the teeth. To achieve active ligation, generallylarge or thick archwires are often used to ensure a snug fit in thearchwire slot.

While orthodontic treatment often proceeds according to the abovetreatment plan, i.e., passive ligation during early stages and activeligation during final stages, it may be desirable in some cases todeviate from that treatment plan. By way of example, when using acertain size archwire (e.g., a threshold size of archwire), it may bedesirable to give the orthodontist or the clinician the option ofselecting the type of ligation he or she desires for securing thearchwire to the bracket. This may allow for greater variability in thetreatment plan to meet the specific needs of any particular patient.Current orthodontic brackets, however, and especially self-ligatingorthodontic brackets, typically do not provide the ability for theorthodontist to select between active and passive ligation of thearchwire in an efficient and straight forward manner.

Thus, while self-ligating brackets have been generally successful,manufacturers of such brackets continually strive to improve their useand functionality. In this regard, there remains a need forself-ligating orthodontic brackets that allow an orthodontist orclinician to select between active and passive ligation of the archwirein an improved manner. In this way, orthodontists may develop treatmentplans that more adequately meet the needs of patients.

SUMMARY OF THE INVENTION

The present invention overcomes the foregoing and other shortcomings anddrawbacks of orthodontic brackets. While the present invention will bedescribed in connection with certain embodiments, it will be understoodthat the present invention is not limited to these embodiments. On thecontrary, the present invention includes all alternatives, modificationsand equivalents as may be included within the spirit and scope of thepresent invention.

In accordance with the principles of the present invention, anorthodontic bracket for coupling an archwire with a tooth comprises abracket body configured to be mounted to the tooth. The bracket bodyincludes an archwire slot that is configured to receive the archwiretherein and has a base surface that at least partly defines the archwireslot. The orthodontic bracket further comprises a slide member that isengaged with the bracket body and that is movable relative to thebracket body between an opened position, a first ligating position, anda second ligating position. In the opened position, the archwire isinsertable into the archwire slot. In the first ligating position and inthe second ligating position, a surface of the slide member bounds thearchwire slot on a side generally opposite to the base surface to retainthe archwire in the archwire slot. The orthodontic bracket furthercomprises a resilient member coupled to one of the slide member and thebracket body. The resilient member is configured to engage the other ofthe slide member and the bracket body. The resilient member has adeformed state that is configured to impose a force that biases theslide member toward the base surface of the archwire slot in at leastone of the first and second ligating positions. In the first ligatingposition, the base surface of the archwire slot and the surface of theslide member are separated by a first distance, and in the secondligating position, the base surface of the archwire slot and the slidemember are separated by a second distance that is different from thefirst distance.

According to one aspect of the present invention, the resilient memberis deformed when in the first ligating position such that the slidemember is biased toward the base surface of the archwire slot when theslide member is in the first ligating position. The first distance maybe less than the second distance.

According to one aspect of the present invention, the force biasing theslide member toward the base surface of the archwire slot is greater inthe first ligating position than in the second ligating position.

According to one aspect of the present invention, the resilient memberis deformed when in the second ligating position such that the slidemember is biased toward the base surface of the archwire slot when inthe second ligating position. The second distance may be less than thefirst distance.

According to one aspect of the present invention, the force biasing theslide member toward the base surface of the archwire slot is greater inthe second ligating position than in the first ligating position.

According to one aspect of the present invention, movement of the slidemember between the opened position, the first ligating position, and thesecond ligating position is along a ligating axis that is generallyperpendicular to an axis of the archwire slot.

According to one aspect of the present invention, a distance of travelof the slide member generally perpendicular to an axis of the archwireslot from the opened position to the first ligating position is lessthan a distance of travel of the slide member generally perpendicular tothe axis of the archwire slot from the opened position to the secondligating position.

According to one aspect of the present invention, the resilient memberincludes a spring pin.

According to one aspect of the present invention, the slide memberengages a portion of the bracket body on both sides of the archwire slotwhen in the second ligating position.

According to one aspect of the present invention, the archwire slotfurther includes a first slot surface and a second slot surfaceextending outwardly from the base surface and the slide member has aleading edge that is adjacent the first slot surface in the openedposition, between the first slot surface and the second slot surface inthe first ligating position, and adjacent the second slot surface in thesecond ligating position.

According to one aspect of the present invention, the surface of theslide member is fixed relative to the base surface of the archwire slotin each of the first ligating position and the second ligating position.

According to one aspect of the present invention, the bracket bodyincludes a wall and the slide member contacts the wall in one of thefirst ligating position and the second ligating position. The wall isconfigured to define a minimum distance between the base surface of thearchwire slot and the surface of the slide member. The slide member maybe configured to contact the wall in the first position. Alternatively,the slide member may be configured to contact the wall in the secondposition.

In accordance with the principles of the present invention, a method oforthodontic treatment with a self-ligating orthodontic bracket attachedto a tooth, the orthodontic bracket including a bracket body having anarchwire slot formed therein, a slide member, and a resilient membercoupled to one of the slide member and the bracket body and configuredto engage the other of the slide member and the bracket body, and anarchwire being disposed in the archwire slot, the method comprisesmoving the slide member generally perpendicularly toward an axis of thearchwire slot from a first ligating position to a second ligatingposition. In the first ligating position, a surface of the slide memberis spaced from a base surface of the archwire slot at a first distance.The surface of the slide member opposes the base surface of the archwireslot so as to form one boundary of the archwire slot and inhibits thearchwire from being removed from the archwire slot. In the secondligating position, the surface of the slide member is spaced from thebase surface of the archwire slot at a second distance that is differentfrom the first distance, forms one boundary of the archwire slot, andinhibits the archwire from being removed from the archwire slot. In oneof the first ligating position and the second ligating position, theresilient member has a deformed state that biases the slide membertoward the base surface of the archwire slot.

According to one aspect of the present invention, the first ligatingposition includes active ligation of the archwire, and the secondligating position includes passive ligation of the archwire, and movingthe slide member includes moving the slide member from active ligationof the archwire to passive ligation of the archwire.

According to one aspect of the present invention, the first ligatingposition includes passive ligation of the archwire and the secondligating position includes active ligation of the archwire, and movingthe slide member includes moving the slide member from passive ligationof the archwire to active ligation of the archwire.

According to one aspect of the present invention, moving the slidemember includes moving the surface of the slide member closer to thebase surface of the archwire slot.

According to one aspect of the present invention, moving the slidemember includes moving the surface of the slide member further from thebase surface of the archwire slot.

According to one aspect of the present invention, the method furthercomprises moving the slide member from the first ligating position to anopened position in which the archwire slot is open, and removing thearchwire from the archwire slot.

According to one aspect of the present invention, moving the slidemember from the first ligating position to the opened position includesmoving the slide member generally perpendicularly away from the axis ofthe archwire slot.

The above and other objectives and advantages of the present inventionshall be made apparent from the accompanying drawings and thedescription thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with the detailed description given below, serve to explain theinvention.

FIG. 1 is a perspective view of an orthodontic bracket according to oneembodiment of the invention, a slide member shown in the passiveposition;

FIG. 2 is an exploded perspective view of the orthodontic bracket shownin FIG. 1;

FIG. 3A is a cross-sectional view of the orthodontic bracket taken alongsection line 3-3 of FIG. 1, depicting the slide member in the openedposition;

FIG. 3B is a cross-sectional view of the orthodontic bracket taken alongsection line 3-3 of FIG. 1, depicting the slide member in the activeposition;

FIG. 3C is a cross-sectional view of the orthodontic bracket taken alongsection line 3-3 of FIG. 1, depicting the slide member in the passiveposition;

FIG. 4 is a cross-sectional view of the orthodontic bracket taken alongsection line 4-4 of FIG. 1;

FIG. 5 is a perspective view of an orthodontic bracket according toanother embodiment of the invention, a slide member shown in the activeposition;

FIG. 6 is an exploded perspective view of the orthodontic bracket shownin FIG. 5;

FIG. 7A is a cross-sectional view of the orthodontic bracket taken alongsection line 7-7 of FIG. 5, depicting the slide member in the openedposition;

FIG. 7B is a cross-sectional view of the orthodontic bracket taken alongsection line 7-7 of FIG. 5, depicting the slide member in the passiveposition;

FIG. 7C is a cross-sectional view of the orthodontic bracket taken alongsection line 7-7 of FIG. 5, depicting the slide member in the activeposition; and

FIG. 8 is a side elevation view of a bracket body according to oneembodiment of the present invention.

DETAILED DESCRIPTION

Although the invention will be described in connection with certainembodiments, the invention is not limited to practice in any onespecific type of self-ligating orthodontic bracket. The description ofthe embodiments of the invention is intended to cover all alternatives,modifications, and equivalent arrangements as may be included within thespirit and scope of the invention as defined by the appended claims. Inparticular, those skilled in the art will recognize that the componentsof the embodiments of the invention described herein could be arrangedin multiple different ways.

With reference generally to the figures, embodiments of the presentinvention include a self-ligating orthodontic bracket having an archwireslot and a movable member movable relative to the archwire slot to anopened position in which an orthodontic archwire may be inserted intothe archwire slot. The movable member may then be moved to one or moreclosed positions in which the archwire is captured within the archwireslot. The closed positions may include at least two positions thatcapture the archwire within the archwire slot. However, the closedpositions differ in their relative position with respect to the archwireslot so as to provide two different effective dimensions of the archwireslot.

In use, it is contemplated that a clinician may operate the movablemember between the at least two closed positions to change the effectivedimension of the archwire slot. In particular, the clinician may operatethe movable member to a first closed position in which the bracketactively ligates an archwire in the archwire slot and then move themovable member to a second closed position in which the bracketpassively ligates the archwire, without changing the archwire. In thissituation, the clinician may alter the ligation mode (i.e., active orpassive) without changing the archwire. Alternatively, the clinician maymove the movable member between a first closed position, in which thebracket passively ligates the archwire, and a second closed position inwhich the bracket actively ligates the archwire. In this sense, theself-ligating brackets according to embodiments of the present inventionare configured to operate in either the active mode or the passive modeand be capable of switching between the modes by movement of the movablemember and without changing the archwire or adding a ligature or anotherdevice.

To that end and referring now to the drawings, and to FIGS. 1 and 2 inparticular, an orthodontic bracket 10 includes a bracket body 12 and amovable closure member coupled to the bracket body 12. In oneembodiment, the movable closure member may include a ligating slide 14slidably coupled with the bracket body 12. While the movable closuremember is described herein as a ligating slide, the invention is not solimited as the movable closure member may include other movablestructures (e.g., latch, spring clip, door, etc.). The bracket body 12includes an archwire slot 16 formed therein configured to receive anarchwire 18 (shown in phantom) for applying corrective forces to theteeth. The ligating slide 14 is movable between an opened position(e.g., FIG. 3A) in which the archwire 18 is insertable into the archwireslot 16; a first ligating position (e.g., FIG. 3B), in which thearchwire 18 is retained in the archwire slot 16 and ligated to thebracket body 12 in one of an active or passive manner; and a secondligating position (e.g., FIG. 3C), in which the archwire 18 is retainedin the archwire slot 16 and ligated to the bracket body 12 in the otherof the active or passive manner. For example, in the embodiment shown inFIGS. 1-4, the first ligating position may be an active ligatingposition, and the second ligating position may be a passive ligatingposition. Alternatively, and as shown in FIGS. 5-7C, the first ligatingposition may be a passive ligating position, and the second ligatingposition may be an active ligating position. In any event, the bracketbody 12 and ligating slide 14 collectively form an orthodontic bracket10 for use in corrective orthodontic treatments.

In addition to the above, the orthodontic bracket 10 further includes amulti-function biasing member coupled to one of the bracket body 12 orligating slide 14 and configured to engage the other of the bracket body12 or ligating slide 14. For example, as explained in more detail below,the biasing member, which in one embodiment includes a resilient member20 (shown in FIGS. 3A-3C), provides a force for biasing the ligatingslide 14 toward the base of the archwire slot 16 in at least one of thefirst and second ligating positions. More particularly, the biasingmember provides a force for biasing the ligating slide 14 toward thebase of the archwire slot 16 at least when the slide is in the activeligating position. In one embodiment, for example, the resilient member20 may include a tubular pin. In this regard, the cross section may becontinuous, that is, the tubular resilient member 20 may be withoutslots or other discontinuities in its sidewall. In this regard, andunlike a slotted tubular spring pin, the perimeter of the resilientmember 20 is generally maintained when the resilient member 20 iselastically deformed. While the biasing member is described herein as aresilient member (e.g., tubular pin), the invention is not so limited asother biasing members may be configured for use in embodiments inaccordance with the invention.

Moreover, resilient member 20 may further provide a retaining featurefor retaining the ligating slide 14 to the bracket body 12 such that theligating slide 14 cannot be separated therefrom during use. As will bediscussed below, in one embodiment, the biasing member may be configuredto engage an aspect of the bracket body 12 to prevent the ligating slide14 from being separated from the bracket body 12. Furthermore, theresilient member 20 may provide a securing mechanism for securing theligating slide 14 in at least the first and second ligating positions.As will be discussed below, in one embodiment, the biasing member may beconfigured to engage aspects of the bracket body 12 such that athreshold level of force must be applied to the ligating slide 14 beforethe ligating slide 14 may be moved away from the first ligating positionor the second ligating position. In an exemplary embodiment, the sameresilient member facilitates all of these various functions.

In an exemplary embodiment, the resilient member 20 may be composed ofNickel Titanium (NiTi) superelastic material. By way of example, oneNiTi composition includes about 55 wt. % nickel (Ni), and about 45 wt. %titanium (Ti) with minor amounts of impurities and which is availablefrom NDC of Fremont, Calif. The mechanical properties of the NiTi alloymay include an ultimate tensile strength of greater than about 155 ksi,an upper plateau of greater than about 55 ksi, and a lower plateau ofgreater than about 25 ksi. The dimensions of the resilient member 20 mayvary depending on the size of the bracket 10. In one embodiment, theresilient member 20 is a generally right circular hollow cylinder havinga diameter of about 0.016 inches and being from about 0.050 inches toabout 0.125 inches in length. The sidewall thickness may measure fromabout 0.001 inches to about 0.004 inches, and may preferably be about0.002 inches to about 0.003 inches.

The orthodontic bracket 10, unless otherwise indicated, is describedherein using a reference frame attached to a labial surface of a toothon the lower jaw. Consequently, as used herein, terms such as labial,lingual, mesial, distal, occlusal, and gingival used to describe bracket10 are relative to the chosen reference frame. The embodiments of theinvention, however, are not limited to the chosen reference frame anddescriptive terms, as the orthodontic bracket 10 may be used on otherteeth and in other orientations within the oral cavity. For example, thebracket 10 may also be coupled to the lingual surface of the tooth andbe within the scope of the invention. Those of ordinary skill in the artwill recognize that the descriptive terms used herein may not directlyapply when there is a change in reference frame. Nevertheless,embodiments of the invention are intended to be independent of locationand orientation within the oral cavity and the relative terms used todescribe embodiments of the orthodontic bracket are to merely provide aclear description of the embodiments in the drawings. As such, therelative terms labial, lingual, mesial, distal, occlusal, and gingivalare in no way limiting the invention to a particular location ororientation.

When mounted to the labial surface of a tooth T (not shown) carried onthe patient's lower jaw and with reference specifically to FIG. 1, thebracket body 12 has a lingual side 22, an occlusal side 24, a gingivalside 26, a mesial side 28, a distal side 30 and a labial side 32. Thelingual side 22 of the bracket body 12 is configured to be secured tothe tooth in any conventional manner, such as for example, by anappropriate orthodontic cement or adhesive or by a band around anadjacent tooth. In one embodiment, the lingual side 22 may further beprovided with a pad (not shown) defining a bonding base that is securedto the surface of the tooth T. With reference to FIGS. 1 and 2, thebracket body 12 includes a base surface 36 and a pair of opposed slotsurfaces 38, 40 projecting labially from the base surface 36 thatcollectively define the archwire slot 16, which may extend in amesial-distal direction from mesial side 28 to distal side 30. The basesurface 36 and slot surfaces 38, 40 are substantially encapsulated orembedded within the material of the bracket body 12 and is configured toreceive the archwire 18 therein.

As shown in FIG. 2, in one embodiment, the bracket body 12 furtherincludes a slide support portion 48 configured to receive the ligatingslide 14 thereon. The slide support portion 48 may generally projectlabially from or be oriented generally perpendicular to the lingual side22 of the bracket body 12. The slide support portion 48 generallydefines a support surface 50 that may slidably engage the ligating slide14 over at least a portion of its translational motion from at least oneof the first and second ligating positions to the opened position. In alabial application (FIG. 1), the support surface 50 is positionedgingivally of the archwire slot 16 and extends in a generallyocclusal-gingival direction.

With continued reference to FIG. 2, the slide support portion 48includes an aperture 52 formed as a through bore in the mesial-distaldirection. For example, in one embodiment, the aperture 52 may take theform of a closed slot through slide support portion 48. The aperture 52may be positioned so that the longitudinal axis of the resilient member20 extends generally parallel to the archwire slot 16 and in themesial-distal direction.

In one embodiment, the aperture 52 is a generally asymmetrical bore thatmay be described as having an irregular configuration. The particularconfiguration of the aperture 52 is dictated by the desired ligationwhen the ligating slide is in the first and second ligating positions.In this regard, cooperation between the resilient member 20 in theaperture 52 may require intentional application of force to close theligating slide 14. A minimum threshold force may be required on theligating slide 14 to move it toward the active and passive positions. Inone embodiment, the minimum threshold force is greater than the slidingweight of the ligating slide 14. In this embodiment, only when the forceon the ligating slide 14 exceeds the minimum threshold force does theresilient member 20 move toward the active and passive positions. Forceson the ligating slide 14 that exceed the minimum threshold force causethe resilient member 20 to elastically deform. By elastic deformation,the strain produced in the resilient member 20 is fully recovered, andthe member 20 reverts to its original shape, upon removal of thedeforming force.

As will be described in detail below, the aperture 52 is configured toslidably engage the resilient member 20 to bias the ligating slide 14toward the base surface 36 of the archwire slot 16 at least when theligating slide 14 is in the active ligating position. For example, inone embodiment, the ligating slide 14 is configured to move relative tothe bracket body 12 in a direction generally perpendicular to thedirection of the archwire slot 16. For example, the ligating slide 14may generally move in a gingival-occlusal direction. Additionally, theligating slide 14 may move relative to the bracket body 12 from theopened position to the first ligating position, then to the secondligating position in a serial or sequential manner. In any event, theresilient member 20 biases the ligating slide 14 in a directiongenerally perpendicular to the slide translational movement and in adirection generally perpendicular to the archwire slot 16. Inparticular, when the ligating slide 14 is in at least the first ligatingposition, the resilient member 20 and the aperture 52 cooperate to biasthe ligating slide 14 toward the base surface 36 of the archwire slot 16(which may be generally in the lingual direction).

As shown in FIGS. 3A-3C, the aperture 52 may include a first lobeportion 56 proximate the gingival side 26. By way of example only, thefirst lobe portion 56 may define a generally circular perimeter along aportion of the aperture 52. The lobe portion 56 may be defined by anaxis 58 and a radius R1. The lobe portion 56 may have a center C1located a height h1 relative to the base surface 36 of the bracket body12. The aperture 52 may further include a second lobe portion 60positioned occlusally relative to the first lobe portion 56. Similar tothe first lobe portion 56, the second lobe portion 60 may be defined bya generally circular perimeter having axis 62 and a radius R2. Thesecond lobe portion 60 may have a center C2 located at a height h2relative to the base surface 36 of the bracket body 12, where h1 is notequal to h2. In one embodiment, the height h2 is less than height h1.The aperture 52 may still further include a third lobe portion 64positioned occlusally relative to the second lobe portion 60, such thatthe lobe portion 64 is proximate the archwire slot 16. Similar to thefirst and second lobe portions 56, 60, the third lobe portion 64 may bedefined by a generally circular perimeter having axis 66 and radius R3.The third lobe portion 64 may have a center C3 located at a height h3relative to the base surface 36 of the bracket body 12, where h3 is notequal to either of h1 or h2. In one embodiment, the height h3 may begreater than the height h2. In another embodiment, the height h3 may begreater than both of the heights h2 and h1. It should be appreciatedthat the relative heights of the first, second, and third lobe portions56, 60, 64 may be dictated by the type and magnitude of the ligationdesired at the opened and first and second ligating positions.

In one embodiment, the aperture 52 may include a central portion 70positioned between and connecting the first lobe portion 56 and thesecond lobe portion 60. The central portion 70 may include a firstsegment 72 that is generally tangent to the first lobe portion 56 andthat is also generally tangent to the second lobe portion 60. The firstlobe portion 56, the second lobe portion 60 and the first segment 72 maygenerally define a portion of a slide track 74.

In addition, the central portion 70 may include a second segment 76opposite the first segment 72. The second segment 76 may be generallytangent to the first lobe portion 56, but may extend in a direction suchthat an extension of the second segment 76 would intersect (rather thanbe tangent to) the second lobe portion 60.

In one embodiment, the orientation of the first segment 72 and thesecond segment 76 of the central portion 70 forms a restriction or pinchpoint 78 between the first lobe portion 56 and the second lobe portion60. The pinch point 78 is generally a narrowing of the aperture 52between the first and second lobe portions 56, 60. Elastic deformationof the resilient member 20 is dictated by the shape of the centralportion 70, particularly the pinch point 78, of the aperture 52. In thisregard, elastic deformation of member 20 may be localized to a region ofcontact with at least the pinch point 78. The pinch point 78 may includenarrowing of the aperture 52 to a dimension that is less than each ofthe largest height (or labial-lingual) dimensions for the first andsecond lobe portions 56, 60, and is less than the diameter of theresilient member 20. Thus, generally the dimensions of the aperture 52disclosed herein are ultimately determined by the dimensions of theresilient member 20. A smaller diameter resilient member 20 willgenerally be received in a correspondingly smaller aperture 52.

By way of example only and not limitation, where each of the first andsecond lobe portions 56, 60 generally define circular bores having radiiR1 and R2, respectively, the pinch point 78 may be measured as aperpendicular distance between the first segment 72 and the nearestopposing portion of the central portion 70. This perpendicular distancemay be less than the diameter of the first lobe portion 56 or less thanthe diameter of the second lobe portion 60 or less than each of thediameters of the first lobe portion 56 and the second lobe portion 60.Further, this dimension may be at least 5% less or in the range of about10% to about 20% less than either diameter of the first or second lobeportions 58, 60. In one embodiment, the radius R2 is less than theradius R1 and the pinch point 78 is sized to be less than twice R2. Byway of example and not limitation, radius R2 may be about 5% to about15% less than radius R1. In an exemplary embodiment, the radius R1 maybe about 0.010 inches and the radius R2 may be about 0.009 inches andthe pinch point 78 may measure about 0.017 inches.

The configuration of the aperture 52, particularly the pinch point 78,controls the movement of the ligating slide from the opened position,shown in FIG. 3A, to the active position, shown in FIG. 3B. In thisregard, when a force on the ligating slide 14 exceeds the minimumthreshold force required to move the ligating slide 14 from the openedposition toward the active position, the resilient member 20 may beelastically deformed. It will be appreciated that depending on theconfiguration of the second segment 76, a gradually increasing force maybe required to continuously move the ligating slide 14 along the slidetrack 74 toward the active position. The rate at which the force isrequired to increase is dictated by the shape of the central portion 70and the properties of the resilient member 20.

With regard to the central portion 70, the second segment 76 is agenerally planar surface and is believed to require a generally linearincrease in force on the ligating slide 14, at least over a portion ofthe movement toward the active position, as shown in FIG. 3B, to deformthe resilient member 20. The resilient member 20 may deform in a mannerwhich allows it to conform to the shape defined by the distances betweenthe region of contact between the resilient member 20 and the firstsegment 72 and the region of contact between the resilient member 20 andthe second segment 76. Because the central portion 70 includes thesegment 72, which provides a gradually decreasing clearance dimensionthat is less than the outside diameter of the resilient member 20, thecentral portion 70 interferes with movement of the resilient member 20.The ligating slide 14 therefore remains substantially in the openedposition unless a force sufficient to elastically deform the resilientmember 20 past the pinch point 78 is applied to the ligating slide 14.

In this regard, the resilient member 20 may elastically deform by achange in the cross-sectional profile of the member 20. This may includea change to a roughly egg-shaped cross section (not shown) in the regionof contact between the resilient member 20 and the aperture 52. Portionsof the resilient member 20 outside of the aperture 52 may notsignificantly elastically deform and thus retain their originalcross-sectional profile. For example, the portions of the resilientmember 20 in the bores 138, 140 may remain substantially circular. Thus,elastic deformation of the resilient member 20 may be localized todiscrete regions of the resilient member 20 in sliding contact with theaperture 52. It will be appreciated that embodiments of the inventionare not limited to any particular form or shape of the resilient member20.

At some force greater than the threshold force required to initiallymove the ligating slide 14 towards the active position, the forceapplied to the ligating slide 14 is sufficient to conform the resilientmember 20 to the dimension of the pinch point 78. At this magnitude offorce, the resilient member 20 is elastically deformed in the region ofcontact with the aperture 52 so that the resilient member 20 may atleast partially squeeze through the pinch point 78. The resilient member20 may elastically deform to an egg-shaped cross section (not shown). Atthe pinch point 78, a leading portion of the resilient member 20 mayreside within the second lobe portion 60 while a remaining portion ofthe resilient member 20 extends into the central portion 70. Theresilient member 20 may reside partially in each of the second lobe 60and the central portion 70. By way of example and not limitation, theforce required to move ligating slide 14 to a position where theresilient member 20 partially enters the second lobe portion 60 mayexceed about 0.1 kgf (kilogram force), and by way of additional example,this force may be from about 0.2 kgf to about 0.8 kgf or from about 0.5kgf to about 0.7 kgf, preferably about 0.6 kgf.

The magnitude of the force required to overcome the threshold forceand/or the threshold sliding force as the ligating slide 14 moves awayfrom the opened position depends on the configuration of the aperture52. This force may therefore be selectively varied by changing theconfiguration of the aperture 52. In this regard, relative angles of thesecond segment 76 and the first segment 72 may be modified to provide adesired force and/or sliding force and the rate at which that force maybe increased. Furthermore, the position of the pinch point 78 may beselected to provide a shorter or longer central portion by which therate of force increase may be changed. The shape of the first and/orsecond segments 72, 76 may be generally planar to provide a linearlyincreasing sliding force when the resilient member 20 is in the centralportion 64. Alternatively, one or both of the segments 72, 76 may becontoured or curved (not shown) to provide a variable sliding force. Theabove-described methods for varying the opening and/or sliding force areexemplary.

Once the opening and/or sliding force meets or exceeds the forcerequired to move the resilient member 20 to a position that is at leastpartially through the pinch point 78, the resilient member 20 mayspontaneously slide or move the remainder of the distance into thesecond lobe portion 60. That is, the leading and remaining portions mayspontaneously move into the second lobe portion 60 in the absence ofadditional external force. More specifically, once a thresholdproportion of the resilient member 20 enters the second lobe portion 60,the sliding movement of the resilient member 20 into the second lobeportion 60 may proceed spontaneously. This movement may be accompaniedby an audible and/or a tactile “click” or “snap” when the resilientmember 20 expands into the second lobe portion 60. By this feature, theclinician may then be assured that the ligating slide 14 has reached itsclosed position and will remain in the closed position under normalforces observed during the orthodontic treatment.

It is believed that the elastic nature of the resilient member 20 causesa natural inclination for the resilient member 20 to return to anundeformed or at least a less deformed configuration than the deformedconfiguration of the resilient member 20 in the vicinity of the pinchpoint 78. Thus, when a threshold portion of the resilient member 20enters the second lobe portion 60 of the aperture 52, the member 20 mayspontaneously release internal elastic energy (by virtue of its deformedcondition). Such a release causes the resilient member 20 in thevicinity of the pinch point 78 to move into and fill the second lobeportion 60 without application of additional external force. In otherwords, only a fractional portion of the resilient member 20 may enterthe second lobe portion 60 when an external force is applied to theligating slide 14 to move the ligating slide 14 to the pinch point 78.The resilient member 20 may move the remainder of the distance into thesecond lobe portion 60 to revert to a configuration having less or noelastic deformation.

In one embodiment, should an insufficient force be applied to theresilient member 20 so that it fails to enter the second lobe portion60, the ligating slide 14 may move, in the absence of an external force,toward the opened position (FIG. 3A) because the resilient member 20 maygradually expand into the larger regions of the central region 70proximate the first lobe portion 56. Ultimately, the resilient member 20may enter the first lobe portion 56.

In one embodiment, as noted above and with reference to FIG. 3B, thethird lobe portion 64 is positioned occlusally and labially relative tothe second lobe portion 60. In embodiments in which the second and thirdlobe portions 60, 64 are generally circular, if the portions of theperimeters of the second and third lobe portions 60, 64 were extended,the perimeters would intersect at points 80 and 82. In this way, theremay not be a central portion between the second and third lobe portions60, 64. A perpendicular distance between the points 80 and 82 may beless than a diameter of one or both of the second and third lobeportions 60, 64, so as to form a pinch point 84 between the second lobeportion 60 and the third lobe portion 64. Similar to the pinch point 78,the pinch point 84 is generally a narrowing of the aperture 52 betweenthe second and third lobe portions 60, 64. The pinch point 84 may have adimension less than or equal to the dimension of the pinch point 78.

As set forth above, the aperture 52 may be asymmetric. In embodimentswhere the first and second lobe portions 56, 60 are generally circular,this asymmetry may, in part, be due to the difference in the radiusdimensions R1, R2, and R3, as well as locations of the pinch points 78,84. In embodiments in which the centers C1, C2, C3 of first, second, andthird lobe portions 56, 60, 64, respectively, are positioned in threedifferent labial-lingual planes, the varying positions may furthercontribute to the asymmetry. The asymmetry in the aperture 52 mayproduce a distinctive tactile response in the movement of the ligatingslide 14. In particular, the asymmetry in the aperture 52 may providethe clinician with a distinctive “click” or “snap” to indicate eachchange between the opened, active, and passive positions of the ligatingslide 14.

With regard to the forces required to move the slide 14, that is, theresilient member 20, from the second lobe portion 60, in which theligating slide 14 is in the active position (FIG. 3B), to the third lobeportion 64, in which the ligating slide 14 is in the passive position(FIG. 3C), the same general principles described above with respect tothe opened to active position transition apply. In this embodiment,however, elastic deformation of the resilient member 20 is affectedsolely by the pinch point 84, as there is no central portionintermediate the second and third lobe portions 60, 64.

With reference to FIG. 2, in the exemplary embodiment shown, the bracketbody 12 includes a mesial and distal shoulder 86 extending from opposedsides of the slide support portion 48. In one embodiment, each shoulder86 is generally defines a surface that is generally parallel with thebase surface 36 of the archwire slot 16. As is shown in FIG. 3B, one ormore of the shoulders 86 may form a stop against which the ligatingslide 14 may reside when it is in the opened position and/or the activeposition. The slot surface 40 extends lingually from the occlusal sideof the shoulder 86. Wall 88 extends lingually from the gingival side ofthe shoulder 86.

With further reference to the exemplary embodiment shown in FIGS. 2 and3B, a track surface 90 is positioned on the mesial and distal sides ofthe slide support portion 48. The track surface 90 generally extendsbetween the wall 88 and the gingival side 26 of the bracket body 12. Thetrack surface 90 has a topography configured to cooperate with theligating slide 14 to achieve the intended function of the bracket 10.

In this regard, the track surface 90 comprises a generally planarlabially-facing surface 92 having a ridge 94 and an incline or ramp 96(shown best in FIG. 3B) positioned thereupon in spaced relation. Thesurface 92 is generally parallel to the base surface 36. The ridge 94and the ramp 96 generally extend labially relative to the planar surface92. The ridge 94 may be positioned proximate the gingival side 26 of thebracket body 12 while the ramp 96 may be positioned adjacent the wall88. The ridge 94 includes a gingival surface 98, a labial surface 99,and an occlusal surface 100 (FIG. 3B). The gingival surface 98 is angledor sloped so as to effectively operate as a camming surface for theligating slide 14. The labial surface 99, which is positionedintermediate the gingival surface 98 and the occlusal surface 100, maybe generally parallel to the base surface 36. The occlusal surface 100may descend from the labial surface 99 to the planar surface 92 at asharp angle generally perpendicular to the planar surface 92. The ramp96 may comprise an angled surface 97 of track surface 90 extendingbetween the generally planar surface 92 and the wall 88. The ramp 96 mayhave a same angle relative to the planar surface 92 as the gingivalsurface 98 of the ridge 94. The ramp 96 may have a small shelf 102comprising a generally planar surface at the labial-most position on theramp 96, adjacent the wall 88. The shelf 102 may be generally parallelto the base surface 36. The shelf 102 and the labial surface 99 may bepositioned at a same height above the planar surface 92.

In another aspect of the exemplary embodiment shown, and as best shownin FIG. 3B, a cutout 106 may be formed in the labial side 32 of thebracket body 12 adjacent slot surface 38, and the cutout 106 may definea labially-facing ledge 108 that lies in a plane that is positionedlabially of a plane in which the shoulders 86 lie. The cutout 106further defines an occlusal surface 110 generally perpendicular to theledge 108. The ledge 108 is configured to engage the ligating slide 14in the passive ligating position. In this way, when the ligating slide14 is in the passive position, the archwire slot 16 effectively has agreater lingual-labial dimension than when the ligating slide 14 is inthe active position. This will be discussed in greater detail below.

With reference to FIG. 2, the ligating slide 14 is generally a U-shapedconfiguration. When mounted to the labial surface of the tooth T carriedon the patient's lower jaw, the ligating slide 14 has a lingual side120, an occlusal side 122, a gingival side 124, a mesial side 126, adistal side 128, and a labial side 130. The ligating slide 14 includes afirst leg or mesial portion 132 and second leg or a distal portion 134that generally define a slide channel 136 therebetween. The slidechannel 136 is dimensioned to slidably cooperate with the slide supportportion 48 on the bracket body 12. In one embodiment, the slide channel136 has a uniform shape and width that generally corresponds to theshape and width of the slide support portion 48 of the bracket body 12such that the slide support portion 48 may be received in the slidechannel 136.

With continued reference to FIG. 2, each of the mesial and distalportions 132, 134 includes at least one through-bore that receives aportion of the resilient member 20. As shown, the mesial portion 132includes a mesial through-bore 138 and the distal portion 134 includes adistal through-bore 140. The bores 138, 140 share a common axis 142. Asshown in FIG. 4, the resilient member 20 is positioned in the bore 138and through the aperture 52 and into the opposing bore 140 along axis142. Thus, the resilient member 20 when coupled to the ligating slide 14moves with the ligating slide 14 and extends through and moves relativeto the aperture 52. By this construction, the resilient member 20 mayprovide a mechanism for securing or retaining the ligating slide 14 tothe bracket body 12 in the opened, active, and/or passive positions.

In one embodiment and with reference to FIG. 3A, the resilient member 20cooperates with the bracket body 12, and more particularly to first,second, and third lobe portions 56, 60, 64 of the aperture 52, to securethe ligating slide 14 to the bracket body 12 in respective opened,active, and passive positions. It will be appreciated that the bore 138and the bore 140 may be sized to be slightly larger than the diameter orequivalent dimension of the resilient member 20. By way of example, thebores 138, 140 may be about 0.002 inches larger in dimension than thelargest corresponding outer dimension of the resilient member 20. By wayof further example, the bores 138, 140 may measure from about 10% toabout 20% larger than the corresponding outer dimension of the resilientmember 20. The resilient member 20 may be dimensioned to fit within thebores 138, 140 and through the aperture 52. During assembly, theresilient member 20 may be press fit or slip fit into bores 138, 140,and/or may be secured therein to prevent relative movement therebetweenusing various processes including staking, tack welding, laser welding,adhesives, or other suitable methods.

In one embodiment and with continued reference to FIG. 2, lingual edgesof the mesial and distal portions 132, 134 each comprise a ligatingsurface 146 adjacent the occlusal side 122 of the ligating slide 14 anda track surface 148 proximate the gingival side 124 of the ligatingslide 14, the track surface 148 being lingual the ligating surface 146.An intermediate wall 150 may connect the ligating surface 146 and thetrack surface 148.

In one embodiment shown in FIGS. 2 and 3B, the ligating surfaces 146 areplanar and are configured to slidingly engage with the shoulders 86and/or the ledge 106 during at least a portion of the movement of theligating slide 14 between the various positions. Portions of each of theligating surfaces 146 may oppose the base surface 36 when the ligatingslide 14 is in the active and passive positions, and thereby effectivelyform a fourth side of the archwire slot 16. In this regard, in theembodiment shown in FIG. 3B, the ligating surfaces 146 form the labialboundary of the archwire slot 16 to capture the archwire 18 (FIG. 1) inthe archwire slot 16 during orthodontic treatment.

In addition, in one embodiment, the ligating surfaces 146 are configuredto abut the mesial and distal shoulders 86 when the ligating slide 14 isin the opened and active positions as is shown in FIGS. 3A and 3B,respectively. As introduced above, the resilient member 20 may bias theligating slide 14 in a direction generally perpendicular to thedirection of translational motion of the ligating slide 14. This mayinclude a direction that is toward the base surface 36 of the archwireslot 16.

As is shown in FIG. 3B, in one embodiment, when the ligating slide 14 isin the active position, the ligating surfaces 146 may not extend thefull height (i.e., from the slot surface 38 to the slot surface 40) ofthe archwire slot 16. In this regard, mesial and distal portions 132,134 further include generally occlusally oriented leading surfaces 152.In the embodiment shown, the leading surfaces 152 do not contact theopposing slot surface 38. Accordingly, there remains a gap 154 betweenthe slot surface 38 and the ligating slide 14 when in the activeligation position.

Similarly, in one embodiment, when the ligating slide 14 is in thepassive position, as is shown in FIG. 3C, the occlusally orientedleading surfaces 152 do not extend to the occlusal surface 110 of thecutout 106. Accordingly, there remains a gap 156 between the occlusalsurface 110 and the ligating slide 14 at this location. The gap 156 maybe sized to receive a tool for forcing the ligating slide 14 to theopened position from either of the passive or active positions.

According to an exemplary embodiment shown in FIG. 3B, the wall 150 hasa height equal to the distance between the generally planar portion 92of the track surface 90 and the shoulder 86. When the ligating slide 14is in the opened and active positions (FIGS. 3A and 3B, respectively), atop of the wall 150 is positioned generally coplanar with the shoulder86. When the ligating slide 14 is in the passive position (FIG. 3C), thewall 150 extends above the shoulder 86 a distance equivalent to a heightbetween the generally planar surface 92 and a labial-most point on theramp 96 of the track surface 90. When the ligating slide 14 is theopened position (FIG. 3A), the wall 150 is spaced a first distance fromthe wall 88. When the ligating slide 14 is in the active position (FIG.3B), the wall 150 is spaced a second distance shorter than the firstdistance from the wall 88. When the ligating slide 14 is the passiveposition (FIG. 3C), the wall 150 abuts the wall 88.

With continued reference to FIGS. 2 and 3A-3C, in one embodiment, thetrack surface 148 of the ligating slide 14 is configured to cooperatewith the track surface 90 of the bracket body 12. In the exemplaryembodiment shown in FIG. 2, the track surface 148 has a leading edge 160at an intersection with the wall 150 (i.e., at an occlusal end of thetrack surface 148). A recess 162 is positioned in the track surface 148proximate the leading edge 160. The recess 162 has an occlusal wall 164and a gingival wall 166. The gingival wall 166 effectively operates asanother cam against the track surface 90.

With further reference to the exemplary embodiment of FIG. 3A, in theopened position, the leading edge 160 of the slide track surface 148 ispositioned occlusally of the ridge 94 of the bracket body 12. The ridge94 is positioned within the recess 162, such that the occlusal side 100of the ridge 94 at least partially contacts the occlusal wall 164 of therecess 162. The gingival wall 166 of the recess 162 extends beyond oroverhangs the gingival side 26 of the bracket body 12. The common axis142 of each of the bores 138, 140 may be aligned with the axis 58 of thefirst lobe portion 56. The axis 1 of the resilient member 20 may also bealigned with the axis 58 depending on the cross-sectional dimensions ofthe resilient member 20. Generally, in this position, and where each ofthe first lobe portion 56 and bores 138, 140 are generally larger indimension than the resilient member 20, the resilient member 20 is in arelaxed, undeformed state and may not bias the ligating slide 14 in anygiven direction. Where the bracket 10 is mounted on the labial surfaceof a lower tooth, gravity, as well as an interaction between theocclusal wall 164 of the recess 162 and the ridge 94, will tend tomaintain the ligating slide 14 in the opened position.

With reference to the exemplary embodiment of FIGS. 3B and 4, in whichthe ligating slide 14 is shown in the active position, the leading edge160 is positioned on the ramp 96 intermediate the generally planarsurface 92 and the shelf 102, the ridge 94 is positioned in the recess162, and the gingival wall 166 of the recess 162 is positioned adjacentto or at least partially abuts the gingival side 98 of the ridge 94. Inthe active position, the resilient member 20 is positioned in the secondlobe portion 60. At least a portion of the second lobe portion 60 mayreside lingually of the mesial and distal bores 138, 140, such that thesecond lobe portion 60 and the bores 138, 140 are not fully aligned. Assuch, and as shown in FIG. 4, a center portion 170 of the resilientmember 20 is positioned lingually relative to end portions 172 thereof.As such, the axis 1 of the resilient member 20 is curved lingually, andthe resilient member 20 imposes a biasing force on the ligating slide 14generally in the lingual direction. More specifically, the resilientmember 20 may bias the ligating slide 14 toward the shoulder 86 and thebase surface 36 of the bracket body 12, which helps to actively ligatethe archwire 18 in the archwire slot 16 (i.e., when the archwire 18substantially fills the archwire slot 16). Accordingly, the resilientmember 20 provides more consistent contact between the ligating slide 14and the bracket body 12.

With reference to FIGS. 2 and 3B, as described above, in the activeposition, the ligating surfaces 146 of ligating slide 14 arecantilevered to extend at least partially over the archwire slot 16. Theligating surfaces 146 extend sufficiently far over the archwire slot 16so as to prevent removal of the archwire 18 therefrom. In this way, theligating surfaces 146 effectively operate as a fourth side of thearchwire slot 16. The depth of the archwire slot 16 in the generallylabial-lingual direction is determined by the position of the shoulders86 relative to the base surface 36 of the archwire slot 16. The biasingforce of the resilient member 20 provides a relatively consistentcontact between the ligating surfaces 146 and the shoulders 86. In oneembodiment, the archwire slot 16 may have a depth of approximately 0.018inch to approximately 0.028 inch. It will be appreciated that for thebracket 10 to actively ligate the archwire 18, the archwire 18 must havea diameter or other dimension that is greater than the depth of thearchwire slot 16 when the ligating slide 14 is in the active position,as is shown in FIG. 3B. For example, the bracket 10 may be active for anarchwire having a 0.020 inch dimension when the ligating slide 14 is inthe active position. In this representative example, the wall 88 is lessthan about 0.020 inch. However, it will be appreciated that archwiressmaller than 0.020 inch may be actively ligated. For example, where thewall 88 is less than 0.016 inch, a 0.016 inch archwire may be activelyligated. Thus, the dimensions of the bracket body 12, for example, theheight of the wall 88, may be adjusted to ligate smaller archwiresaccording to the principles disclosed herein.

With continued reference to the exemplary embodiment shown in FIGS. 3Aand 3B, and as will be described further below, in order for theligating slide 14 to pass from the opened position to the activeposition (and for the leading edge 160 to partially ascend the ramp 96),a sufficient force must be applied to the ligating slide 14 to pass theresilient member 20 through the pinch point 78 between the first andsecond lobe portions 56, 60 of the aperture 52. A similar force islikewise required to move the ligating slide 14 in the oppositedirection, from the active position (FIG. 3B) to the opened position(FIG. 3A).

With reference to the exemplary embodiment of FIGS. 2 and 3C, when theligating slide 14 is in the passive position, the leading edge 160 issupported on the shelf 102 (adjacent the wall 88), the gingival wall 166of the recess 162 is supported on the ridge 94, and an entire length ofthe track surface 148 at the recess 162 is spaced from the track 90. Inthe passive position, the resilient member 20 is positioned in the thirdlobe portion 64. The third lobe portion 64 may be aligned with themesial and distal bores 138, 140 (labeled in FIG. 2), or at least aportion of the third lobe portion 64 may reside lingually of the bores138, 140. In an embodiment in which at least a portion of the third lobeportion 64 resides lingually of the bores 138, 140, there may be betteralignment between the third lobe portion 64 and the bores 138, 140 thanbetween the second lobe portion 60 and the bores 138, 140. Nonetheless,the center portion 170 of the resilient member 20 may be positionedslightly lingually relative to the end portions 172 thereof. As such,the axis 1 of the resilient member 20 may be slightly curved lingually(as is shown in FIG. 4), and the resilient member 20 may impose abiasing force on the ligating slide 14 generally in the lingualdirection.

The resilient member 20 slightly biases the ligating slide 14 toward theledge 108 and the bracket base 36. As mentioned above, in the passiveposition, the ligating surfaces 146 of the ligating slide 14 effectivelyoperate as a fourth side to the archwire slot 16. In the passiveposition, the ligating slide 14 inhibits removal of the archwire 18 fromthe archwire slot 16 without substantially inhibiting movement therein(i.e. when the archwire 18 is smaller than the archwire slot 16). In oneembodiment, the archwire slot 16 may have a depth of approximately0.020-0.027 inches. More specifically, in one embodiment, the archwireslot 16 may have a depth of approximately 0.027 inches. In order forthis embodiment to passively ligate the archwire 18, the archwire 18must have a diameter or other dimension of less than 0.027 inches. Ifthe diameter of the archwire 18 is greater than 0.027 inches, thearchwire 18 may experience active ligation.

With continued reference to FIGS. 3B and 3C, in order for the ligatingslide 14 to pass from the active position (FIG. 3B) to the passiveposition (FIG. 3C) (and for the leading edge 160 and the gingival edge166 to ascend the respective shelf 102 and ridge 94), a sufficient forcemust be applied to the ligating slide 14 to pass the resilient member 20through the pinch point 84 between the second and third lobe portions60, 64 of the aperture 52. A similar force is likewise required to movethe ligating slide 14 in the opposite direction, that is, from thepassive position (FIG. 3C) to the active position (FIG. 3B).

Additionally, in one embodiment, and with reference to FIG. 1, thebracket body 12 may include an occlusal tie wing 176. The ligating slide14 may also include a gingival tie wing 178. It will be appreciated thatthe opposing tie wings 176, 178 may provide a region in which theclinician may engage a ligature, for example, to provide additionalpressure on the ligating slide 14 to maintain it against the bracketbody 12 and in the active or passive positions during treatment.

With reference now to an embodiment of the present invention shown inFIGS. 5-7C, an orthodontic bracket 200 is described. The samedescription and reference numerals used to describe the embodiment ofthe bracket 10 shown in FIGS. 1-4 apply to bracket 200 unless indicatedotherwise. Unlike the bracket 10, which converts from the openedposition to the active position to the passive position, the orthodonticbracket 200 converts from an opened position to a passive position to anactive position. The bracket 200 includes a bracket body 202 and aligating slide 204 slidably coupled with the bracket body 202.

With reference to FIG. 6, the bracket body 202 includes a slide supportportion 206 configured to receive the ligating slide 204 thereon. Theslide support portion 206 includes an aperture 208 formed as athrough-bore in the mesial-distal direction. Similar to the aperture 52in the bracket 10, in one embodiment, the aperture 208 is a generallyasymmetrical bore that may be described as having an irregularconfiguration.

As shown in FIGS. 7A-7C, the aperture 208 may include a first lobeportion 210 proximate the gingival side 26. By way of example only, thefirst lobe portion 210 may define a generally circular perimeter along aportion of the aperture 208. The lobe portion 210 may be defined by anaxis 212 and a radius R1. The lobe portion 210 may have a center C1located a height h1 relative to the base surface 36 of the bracket body202. The aperture 208 may further include a second lobe portion 214positioned occlusally relative to the first lobe portion 210. Similar tothe first lobe portion 210, the second lobe portion 214 may be definedby a generally circular perimeter having axis 216 and a radius R2. Thesecond lobe portion 214 may have a center C2 located at a height h2relative to the base surface 36 of the bracket body 202, where h1 is notequal to h2. In one embodiment, the height h2 is slightly less thanheight h1. Thus, the second lobe portion 214 is positioned slightlylingually of the first lobe portion 210. The aperture 208 may stillfurther include a third lobe portion 218 positioned occlusally relativeto the second lobe portion 214, such that the lobe portion 218 isproximate the archwire slot 16. Similar to the first and second lobeportions 210, 214, the third lobe portion 218 may be defined by agenerally circular perimeter having axis 220 and radius R3. The thirdlobe portion 220 may have a center C3 located at a height h3 relative tothe base surface 36 of the bracket body 202, where h3 is not equal toeither of h1 or h2. In one embodiment, the height h3 may be less thanboth h1 and h2. Thus, the third lobe portion 218 is positioned slightlylingually of the second lobe portion 214.

In one embodiment, the aperture 208 may include a central portion 222positioned between and connecting the first lobe portion 210 and thesecond lobe portion 214. The central portion 222 may include a firstsegment 224. The first segment 224 may be tangent to the first lobeportion 210, but may extend in a direction such that an extension of thefirst segment 224 would intersect (rather than be tangent to) the secondlobe portion 214. The first lobe portion 210, the second lobe portion214, and the first segment 224 may generally define a portion of a slidetrack 226. In addition, the central portion 222 may include a secondsegment 228 opposite the first segment 224. The second segment 228 maycomprise an arcuate curve running between the first lobe portion 210 andthe second lobe portion 214.

In one embodiment, the orientation of the first segment 224 and thesecond segment 228 of the central portion 222 forms a restriction orpinch point 230 between the first lobe portion 210 and the second lobeportion 214. Dimensions of the pinch point 230 may be similar to thosedescribed above with respect to aperture 52 of the orthodontic bracket10. Generally, the smallest dimension of the pinch point 230 is lessthan the diameter of the resilient member 20.

In one embodiment, the aperture 208 may further include a centralportion 232 positioned between and connecting the second lobe portion214 and the third lobe portion 218. The central portion 232 may merelycomprise a point 234 on the lingual portion of the slide track 226 at apoint where the second and third lobe portions 214, 218 would intersectif they had complete perimeters. The central portion 232 may alsoinclude a segment 236 that is tangent to the second lobe portion 214 andthe third lobe portion 218.

In one embodiment, the orientation of the point 234 and the segment 236of the central portion 232 forms a restriction or pinch point 238between the second lobe portion 214 and the third lobe portion 218.Dimensions of the pinch point 238 may be similar to those describedabove with respect to aperture 52 of the orthodontic bracket 10.

With reference to FIGS. 6-7A, and as described above with respect to thebracket 10, the bracket body 202 includes mesial and distal shoulders244. The bracket body 202 may further include a cutout 248 that may beformed in the labial side 32 of the bracket body 202 adjacent the slotsurface 38, and the cutout 248 may define a ledge 250. Unlike theembodiment described above, the ledge 250 may be in a same plane as theshoulders 244. The cutout 248 may further define an occlusal surface 252generally perpendicular to the ledge 250. Both the shoulders 244 and theledge 250 are configured to engage the ligating slide 202 in the activeposition, as is shown in FIG. 7C.

With further reference to FIGS. 6-7C, a surface 254 is positioned oneach mesial and distal side of the slide support portion 206. Thesurface 254 may be generally planar so as to correspond with a generallyplanar lingual edge of the ligating slide 204. Unlike the embodimentdescribed above, the surface 254 may not affect a lingual-labialposition of the ligating slide 204. On each mesial and distal side ofthe slide support portion 206, a wall 256 also extends lingually fromthe gingival side of the shoulder 244.

In one embodiment, a topography of the slide support portion 206 may beconfigured to cooperate with the ligating slide 204 so as to affect alingual-labial position thereof. In an exemplary embodiment shown inFIGS. 6-7C, the slide support portion 206 may include two groovespositioned therein. A first groove 258 is positioned substantiallylabial the second lobe portion 214. A second groove 260 is positioned inspaced relation to the first groove 258 substantially labially of theshoulder 244. The first groove 258 has a gingival wall 262 leading to abase 264 of the groove 258. The gingival wall 262 is angled so as toeffectively operate as a camming surface for a camming member of theligating slide 204, as described in detail below. The second groove 260also has a gingival wall 266 and a base 268, similar to the respectivewall 262 and base 264.

With reference to FIG. 6, the ligating slide 204 is generally a U-shapedconfiguration. The ligating slide 204 includes a first leg or mesialportion 280 and second leg or a distal portion 282 that generally definea slide channel 284 therebetween. The mesial portion 280 includes amesial through bore 286, and the distal portion 282 includes a distalthrough bore 288 having a common axis 287 and the same relativeconfigurations as described above with respect to the bracket 10. Theslide channel 284 is dimensioned to slidably cooperate with the slidesupport portion 206. In one embodiment, the slide channel 284 has auniform width that generally corresponds to the shape of the slidesupport portion 206 of the bracket body 202.

With continued reference to FIG. 6, in one embodiment, the mesial anddistal portions 280, 282 each have a generally occlusally orientedleading surface 290 configured to contact the occlusal surface 252 ofthe cutout 248. Lingual edges of the mesial and distal portions 280, 282each comprise a surface 291 adjacent the occlusal side 122 of theligating slide 204, and a surface 292 proximate the gingival side 124 ofthe ligating slide 204 and positioned lingually relative to the surface291. The surfaces 291 are configured to contact the shoulders 244 and/orthe ledge 250. The surfaces 292 are configured to contact the surfaces254 of the bracket body 202, and in one embodiment, the surfaces 292 aregenerally planar. A labial-lingual wall 293 may connect the surface 291and the surface 292. The wall 293 is configured to contact the wall 256.

In one embodiment, the slide channel 284 is defined by a labial surface294 (i.e., a lingual surface of the ligating slide 204) that isconfigured to contact and slide against the slide support surface 206.The surface 294 includes a first protrusion 296 generally correspondingin shape and size to the groove 258 in the slide support surface 206 anda second protrusion 298 generally corresponding in shape and size to thegroove 260. The protrusions 296, 298 are configured to effectivelyoperate as camming members that cooperate with the gingival walls 262,266 of the first and second grooves 258, 260. A distance between theprotrusions 296, 298 may be generally equal to a distance between thegingival walls 262, 266 of the grooves 258, 260.

With reference to the exemplary embodiment of FIG. 7A, in the openedposition, the protrusion 296 is supported on the slide support surface206 proximate the gingival side 26 of the bracket body 202. Theprotrusion 298 is supported on the slide support surface 206 occlusallyof the groove 258. The common axis 287 (FIG. 6) of each of the bores286, 288 may be aligned with the axis 212 of the first lobe portion 210.The axis 1 of the resilient member 20 may also be aligned with the axis212 depending on the cross-sectional dimensions of the resilient member20. Generally, in this position, and where each of the first lobeportion 210 and bores 286, 288 are generally larger in dimension thanthe resilient member 20, the resilient member 20 is in a relaxed,undeformed state and may not bias the ligating slide 204 in any givendirection. In the opened position, the ligating slide 204 may notcontact the surface 254 or the shoulders 244 of the bracket body 202.Where the bracket 10 is mounted on the labial surface of a lower tooth,gravity will tend to maintain the ligating slide 204 in the openedposition.

With reference to the exemplary embodiment of FIG. 7B, in the passiveposition, the protrusion 296 is supported on the slide support surface206 at least partially gingivally of the groove 258, and the protrusion298 is supported at least partially gingivally of the groove 260. In oneembodiment, the protrusions 296, 298 may be positioned at leastpartially labial the grooves 258, 260, so as to partially overhang thewalls 262, 266, as shown. In the passive position, the resilient member20 is positioned in the second lobe portion 214. The second lobe portion214 may be aligned with the mesial and distal bores 286, 288, or atleast a portion of the second lobe portion 218 may reside lingual thebores 286, 288 (FIG. 6).

In the embodiment in which at least a portion of the second lobe portion218 resides lingually of the bores 138, 140 (FIG. 6), the center portion170 of the resilient member 20 may be positioned slightly linguallyrelative to the end portions 172 thereof. As such, the axis 1 of theresilient member 20 may be slightly curved lingually, and the resilientmember 20 may impose a biasing force on the ligating slide 204. As such,the resilient member 20 slightly biases the ligating slide 204 towardthe base surface 36.

In the passive position, as is shown in FIG. 7B, the surfaces 291 atleast partially extend over the archwire slot 16 so as to preventremoval of the archwire 18 therefrom. A gap 300 may be present betweenthe occlusally leading surface 290 and the slot surface 38. Nonetheless,the surfaces 291 may effectively operate as a fourth side of thearchwire slot 16. In the passive position, the ligating slide 204inhibits removal of the archwire 18 from the archwire slot 16 withoutsubstantially inhibiting movement therein, so long as the archwire 18does not substantially fill the extended archwire slot 16.

With continued reference to FIG. 7B, in order for the ligating slide 204to pass from the opened position (FIG. 7A) to the passive position (FIG.7B) (and for the protrusion 298 to pass over the groove 260), asufficient force must be applied to the ligating slide 204 to pass theresilient member 20 through the pinch point 230 between the first andsecond lobe portions 210, 214 of the aperture 208. A substantially equalforce is required to pass from the passive position back to the openedposition. In the passive position, the ligating slide 204 may notcontact the surface 254 or the shoulder 244 of the bracket body 202.

With reference to the exemplary embodiment of FIG. 7C, in the activeposition, the protrusion 296 is positioned in the groove 258, and theprotrusion 298 is positioned in the groove 260. In this embodiment,because a height of the protrusions is substantially equal to a depth ofthe grooves, almost the entire surface 294 of the slide channel 284 isin contact with the slide support portion 206 of the bracket body 202.In the active position, the resilient member 20 is positioned in thethird lobe portion 218, as shown. At least a portion of the third lobeportion 218 may reside lingually of the mesial and distal bores 286,288, such that the third lobe portion 218 and the bores 286, 288 are notfully aligned. The relative misalignment between the bores 286, 288 andthe third lobe portion 218 requires the resilient member 20 to bendslightly, as is described below.

With continued reference to FIG. 7C, in order for the ligating slide 204to pass from the passive position (FIG. 7B) to the active position (FIG.7C), a sufficient force must be applied to the ligating slide 204 topass the resilient member 20 through the pinch point 238 between thesecond and third lobe portions 214, 218 of the aperture 208. In theactive position, an entire length of the lingual surface 292 and thewall 293 of the ligating slide 204 may contact the bracket body 202. Inanother embodiment, the occlusally leading surfaces 290 of the ligatingslide 204 may contact the occlusal surface 252 of the cutout 248.

When the ligating slide 204 is in the active position, shown in FIG. 7C,the center portion 170 (FIG. 4) of the resilient member 20, whichgenerally includes at least a portion of the resilient member 20 withinthe aperture 208 is positioned lingually relative to end portions 172thereof. Although not shown, the axis 1 of the resilient member 20 iscurved lingually, and the resilient member 20 imposes a biasing force onthe ligating slide 204. More specifically, the resilient member 20 maybias the ligating slide 204 toward the shoulders 244, the ledge 250, andthe base surface 36 of the bracket body 202, which helps to activelyligate the archwire 18 in the archwire slot 16 (i.e. when the archwire18 substantially fills the archwire slot 16). Accordingly, the resilientmember 20 provides more consistent contact between the ligating slide204 and the bracket body 202. For example, the bias may provide moreconsistent contact between the surfaces 291 with the shoulders 244 andthe ledge 250. The depth of the archwire slot 16 is equal to the heightof the shoulders 244 and the ledge 250. Due to the biasing of theligating slide 204 against the shoulders 244 and the ledge 250, othertolerance variations may no longer have a bearing on the close fitbetween the archwire slot 16 and the archwire 18.

In another embodiment, and with reference to FIG. 8, the bracket body300 may include the aperture 302 having more than three lobe portions asdescribed above. In this case, the clinician may move the ligating slide(not shown) from a first lobe portion 304 to a second lobe portion 306to a third lobe portion 308 to a fourth lobe portion 310. Correspondingstep positions 312, 314, and 316 provide support positions for the slideat each of the lobe portions. While four lobe portions are shown,embodiments of the present invention are not limited to three or fourlobe portions, as the aperture 302 may include additional lobe portions.The number of lobe portions may be determined, for example, by the sizeof the resilient member 20. As shown in FIG. 8, the lobe portions 304,306, 308, 310 may be arranged to provide a gradually descendingconfiguration relative to the slot surface 36. The descending,stairstepping-like configuration may be advantageous should theclinician desire to actively ligate gradually decreasing archwire sizesor to actively ligate gradually increasing archwire sizes. For example,when the ligating slide and resilient member 20 (not shown) are in thelobe portion 304, the clinician may insert a relatively small archwireinto the archwire slot 16 and then move the slide (not shown) to thelobe portion 310 to actively ligate the small archwire.

During the course of treatment, the clinician may desire to increase thearchwire size, in which case the clinician, after inserting the largerarchwire, may move the slide to the lobe portion 308. In this position,the slide may actively ligate the larger archwire. With continuingtreatment the clinician may increase the archwire size again andactively ligate the larger archwire by moving the slide to the lobeportion 306. A similar methodology may be utilized for a graduallydecreasing archwire size. In addition, it will be appreciated that thebracket 300 may be utilized for passive ligation with a change inarchwire sizes. For example, where the lobe portion 310 actively ligatesthe archwire, the clinician may position the slide according to the lobeportion 308 to passively ligate the same archwire. Multiple combinationsof active and passive ligation techniques may be utilized by combiningthe multiple slide positions associated with the lobe portions 304, 306,308, and 310 in combination with multiple archwire sizes.

While the present invention has been illustrated by a description ofvarious preferred embodiments and while these embodiments have beendescribed in some detail, it is not the intention of the inventor torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. By way of example, while the embodimentsdescribed herein show the resilient member pushing the ligating slide inthe direction of the slide motion, the resilient members may beconfigured to pull the ligating slide toward the base surface of thearchwire slot.

Thus, the various features of the invention may be used alone or in anycombination depending on the needs and preferences of the user.

What is claimed is:
 1. An orthodontic bracket for coupling an archwirewith a tooth, comprising: a bracket body configured to be mounted to thetooth, the bracket body including an archwire slot configured to receivethe archwire therein and having a base surface that at least partlydefines the archwire slot; a slide member movable relative to thebracket body between an opened position, a first ligating position, anda second ligating position, wherein in the first ligating position andin the second ligating position, a surface of the slide member boundsthe archwire slot on a side generally opposite to the base surface; anda resilient member coupled to one of the slide member and the bracketbody and configured to movably engage the other of the slide member andthe bracket body, the resilient member being configured to bias theslide member toward the base surface of the archwire slot in at leastone of the first and second ligating positions, wherein in the firstligating position, the base surface of the archwire slot and the surfaceof the slide member are separated by a first distance and, in the secondligating position, the base surface of the archwire slot and the slidemember are separated by a second distance that is different from thefirst distance.
 2. The orthodontic bracket of claim 1, wherein theresilient member is deformed when in the first ligating position suchthat the slide member is biased toward the base surface of the archwireslot.
 3. The orthodontic bracket of claim 1, wherein the first distanceis less than the second distance.
 4. The orthodontic bracket of claim 1,wherein the force biasing the slide member toward the base surface ofthe archwire slot is greater in the first ligating position than in thesecond ligating position.
 5. The orthodontic bracket of claim 1, whereinthe resilient member is deformed when in the second ligating positionsuch that the slide member is biased toward the base surface of thearchwire slot when in the second ligating position.
 6. The orthodonticbracket of claim 5, wherein the second distance is less than the firstdistance.
 7. The orthodontic bracket of claim 1, wherein the forcebiasing the slide member toward the base surface of the archwire slot isgreater in the second ligating position than in the first ligatingposition.
 8. The orthodontic bracket of claim 1, wherein movement of theslide member between the opened position, the first ligating position,and the second ligating position is along a ligating axis that isgenerally perpendicular to an axis of the archwire slot.
 9. Theorthodontic bracket of claim 1, wherein a distance of travel of theslide member generally perpendicular to an axis of the archwire slotfrom the opened position to the first ligating position is less than adistance of travel of the slide member generally perpendicular to theaxis of the archwire slot from the opened position to the secondligating position.
 10. The orthodontic bracket of claim 1, wherein thearchwire slot further includes a first slot surface and a second slotsurface extending outwardly from the base surface and the slide memberhas a leading edge that is adjacent the first slot surface in the openedposition, between the first slot surface and the second slot surface inthe first ligating position, and adjacent the second slot surface in thesecond ligating position.
 11. The orthodontic bracket of claim 1,wherein the surface of the slide member is fixed relative to the basesurface of the archwire slot in each of the first ligating position andthe second ligating position.
 12. The orthodontic bracket of claim 1,wherein the bracket body includes a wall and the slide member contactsthe wall in one of the first ligating position and the second ligatingposition, the wall being configured to define a minimum distance betweenthe base surface of the archwire slot and the surface of the slidemember.
 13. The orthodontic bracket of claim 12, wherein the slidemember is configured to contact the wall in the first position.
 14. Theorthodontic bracket of claim 1, wherein the slide member includes atleast one bore and the bracket body includes an aperture, the resilientmember being movable within the aperture and being fixed within the atleast one bore, wherein the aperture is asymmetric about a planegenerally parallel to the base surface and has at least one dimensionsized to cause the resilient member to deform during movement of theslide between the first ligating position and the second ligatingposition.
 15. A method of orthodontic treatment with a self-ligatingorthodontic bracket attached to a tooth, the orthodontic bracketincluding a bracket body having an archwire slot formed therein, a slidemember, and a resilient member coupled to one of the slide member andthe bracket body and configured to engage the other of the slide memberand the bracket body, and an archwire being disposed in the archwireslot, the method comprising: moving the slide member generallyperpendicularly toward an axis of the archwire slot from a firstligating position to a second ligating position, wherein, in the firstligating position, a surface of the slide member is spaced from a basesurface of the archwire slot at a first distance, the surface of theslide member opposes the base surface of the archwire slot so as to formone boundary of the archwire slot, wherein, in the second ligatingposition, the surface of the slide member is spaced from the basesurface of the archwire slot at a second distance that is different fromthe first distance, and forms one boundary of the archwire slot,wherein, in one of the first ligating position and the second ligatingposition, the resilient member has a deformed state that biases theslide member toward the base surface of the archwire slot, and whereinthe first ligating position includes active ligation of the archwire andthe second ligating position includes passive ligation of the archwireand moving the slide member includes moving the slide member from activeligation of the archwire to passive ligation of the archwire.
 16. Themethod of claim 15, wherein during moving of the slide member, theresilient member is deformed.
 17. The method of claim 15, wherein movingthe slide member to the first ligating position deforms the resilientmember and the resilient member remains deformed in the first ligatingposition.
 18. The method of claim 15, wherein moving the slide memberincludes moving the surface of the slide member closer to the basesurface of the archwire slot.
 19. The method of claim 15, wherein movingthe slide member includes moving the surface of the slide member furtherfrom the base surface of the archwire slot.
 20. The method of claim 15,further comprising moving the slide member from the first ligatingposition to an opened position in which the archwire slot is open, andremoving the archwire from the archwire slot.